Former Malcolm in the Middle star Frankie Muniz had major health scare last week. According to TMZ, the 26-year-old actor suffered a "mini-stroke," the cause of which is reportedly stumping doctors. 

Friends of the actor rushed him to an Arizona emergency room late last week when they noticed he was "acting really weird" and having trouble understanding words and speaking. Doctors were able to determine that Muniz had suffered a small stroke, but have been unable to determine why. 

Muniz is, fortunately, OK, though, and even joked about the incident on his Twitter earlier today:

Doctors have reportedly run tests on the actor in an attempt to determine the cause.

RELATED: The 25 Most Annoying Movie Characters

[via TMZ]